First turnip moth of the year captured at Wellesbourne

We found our first male turnip moth in one of our pheromone traps today. This is very 'late' compared with previous years - another effect of the cold spring.

Several years ago, data on trap captures were used to estimate a day-degree (D^o) sum for the start of flight activity by male turnip moths. This was 340 D^o above a base of 7^oC. Up to yesterday we had accumulated 310D^o, so this appears to be quite a reliable estimate!

The cutworm model is a computer programme that uses weather data to predict the rate of development of turnip moth eggs and caterpillars. It also predicts the level of rain-induced mortality among the early-instar caterpillars. Output from this model is available on the HDC Pest Bulletin web site. Cutworm caterpillars are shown below.

Rosemary Collier : 13 Jun 2013 15:40 |  Comments (0) |  Report a problem